This invention relates generally to medical imaging system patient tables, and more particularly, to drive and control systems in the patient tables.
In medical imaging systems such as PET, a patient is scanned by translating the patient within a bore in a gantry. The gantry includes various detectors that scan the patient. For scanning, the patient is translated along an axis defined by the gantry. A patient table, provided with a drive, supports and translates the patient along the defined axis during the scan. The patient table translates along the defined axis in two directions, namely, an insertion direction and an extraction direction.
In the extraction direction, the patient table drive provides a force to extract the patient from within the gantry. This extraction force needs to be sufficiently large to overcome the forces of friction and loads. In the insertion direction, the patient table drive provides a force to translate the patient within the bore of the gantry. This insertion force needs to be sufficiently small to ensure that the patient or any other person, such as a clinician, may not sustain crushing injuries.
Apart from the above-mentioned requirements, the patient table is required to satisfy some other conditions to ensure the safety of the patient. For example, during any software command, emergency-stop command, or power outage, the patient table needs to be released from the patient table drive, in order to enable drive-free motion, thereby enabling the manual extraction of the patient from within the gantry bore
Further, to use the patient table during transportation, such as in a mobile van, the patient table needs to be safely locked for transportation. In conventional patient tables, such, as a PET/CT table, a user inserts a transport lock pin, in order to safely lock the patient table for transportation. This may prove hazardous if the user fails to lock the patient table. In addition, the table needs to remain locked if there is a power failure during transportation of the system.